Green eyes are always evil… in Bionicle.  
-DrMaddWorld

except Sonic always had green eyes in-story, they just did not show it because of the art style.

@gg666
 
Also, since when has it been stated/implied that alicorn == princess?

I agree with Sjogre about the coronation possibly being related to Cadance. Remember all those pictures of Sombra’s horn getting left behind when he got destroyed? Maybe the Crystal Empire is joining Equestria and the coronation is Celestia/Luna officially recognizing Cadance as their leader. And guess who could show up and cause trouble during the coronation, Sombra.
 
Anyway, that’s just speculation on my part and either way I don’t mind too much about alicorn Twilight. I think if it did happen and was permanent, they could still find a way to write it so that it works out.

@Grieffon  
And what about all the merch coming out AFTER the finale where twi ISN’t And Alicorn?
 
Just because Twi will fullfil her destiny does not mean that destiny is 100% certainly going to be conected to the title. He deastiny could be ANYTHING, literally anything.

^bp knows what’s up.

I swear the whole fact about ‘MLP is a show to sell toys and always has been’ keeps becoming a new realization to people everytime it’s meantioned.

Over-reacting is for idiots.  
Real bronies dont go around screaming “Its the end of the world as we know it!” all because of a cartoon…

@Grieffon
 
The only official Hasbro plush Twilight Sparkle I could find didn’t have wings. For what it’s worth, the official one did have similar hair.
 
That leaves one sticker out of a book full of them, and a poster. Even together, that isn’t compelling evidence.
 
The coronation line could very well reference a princess becoming a queen, and Queens ruled the Crystal Empire in times past. Like it or not, Cadance and the Empire have gotten at least three episodes this season, so referring to Cadance again is very possible.

This situation is in no way shape or form similar to the other you’ve noted above. Fandoms usually have these kind of reactions if they feel that some deviation will ultimately harm the product in the end. There have been many cases of this from books to sports.

@Sjogre  
That plush is official. And so is the banner in the left pic. And so is this
 

 
And some other merch that I can’t remember. All official.
 
And in the latest commercials, there are “one mare will achieve her destiny” and “princess coronation” while showing scenes of Twilight. Don’t “Princess Cadance”, she’s already a princess, and there’s no point emphasizing her after the Canterlot Wedding.

@Grieffon
 
Seriously? A plushy? Aside from the question of whether or not that’s official merch, claiming that a plushy means that Twilight will become a winged unicorn is like saying that everyone with a so-soft baby tool is going to be age regressed.
 
I thought that you’d seen a playset or a brushable. Heck, even a blindbag figure.

@Sjogre  

@Grieffon
 
What Winged Unicorn toy? I haven’t seen or heard of one anywhere.
 
You have some insider info that you aren’t sharing?

@gg666  
I guess the show hasn’t outlined it well enough.

alicorn /= god
 
why is that so hard to understand. ITS JUST WINGS

Uh, hello? Princess Cadence, anyone? The fandom flipped its shit over her last year, and then…nothing happened. Cadence turned out to be pretty awesome. Lots of noise and fury signifying nothing. Seriously, people, lighten the fuck up.  
Need I remind you the show isn’t actually made with us in mind? Hmm? It’s for LITTLE GIRLS. I think a lot of people forget that. Is a little girl gonna think a princess version of Twilight is neat? Hell yes they are.  
Stop yer bitchin’ already. Jesus.

Let’s go through the facts shall we?
 
1. Twilight becoming an alicorn is an extremely likely scenario.  
Face it, with the alicorn Twi toy and all the alicorn Twi appearing in the recent merchandise, combining with “one mare will achieve her destiny” and “princess coronation”, it’s quite obvious she will become an alicorn princess.
 
2. Twilight becoming an alicorn PERMANENTLY almost has no chance of happening.  
Why? Because she won’t be able to live a normal life anymore. Everyone, save her friends, will treat her the same way as Celestia, with respect and fear. That will destroy the slice-of-life nature of the show.

I think in season 4 ALL the ponies should wear socks, wear colored contact lens, and for the sake of fashion Twilight should wear a stylish pair of wings.  
I guess what I’m trying to say is that, everypony should just chill out and enjoy what ever the show throws at us.

What if she becomes a Princess without being an Alicorn?
 
Blueblood is a Prince and he sill just a Unicorn.

@ShinyCrobat  
Exhaustception.

@441  
You do see how that doesn’t make a lot of sense right? You’re saying you’re tired of hearing people who are tired of hearing people.

@DudeManGuy
 
Princess Cadance says hi. She’s pretty much proof that supreme power is exclusive to Luna and Celestia.

Am I freaking out over this? No. There’s really no point in doing so.
 
Am I okay with what could potentially happen? Not in any way, shape, or form.
 
Without going into the “why,” just let me say this. These writers were able to sell the vast majority of us on Cadance, who was very blatantly a toy insert.
 
If there is ANY team that can convincingly land this whopper, it’s this one.
 
Let’s do this, writers. I humbly invite you to make me eat my words.

Turning into a being best described in-universe as a physical god isn’t on the same level of character change as eye color, especially considering how eye color means nothing in the Sonic universe.